the next Constellation
by Catrowline
Summary: What if Sirius Black had a sister, Cassiopeia, as well as a brother? What if she followed his footseps at Hogwarts into Gryffindor? And it looks like something mysterious relies on her... Will she live, or will Evil win? Remus X Cassiopeia, rated M for (a lot of) swear words.
1. Chapter 1: The Beginning of a First-year

**Author's note**

 **Hello there! I deleted the story « it was perfect » because I didn't have any insperation for it anymore. This is a totally different approach, but my dear Remus is the one I always choose when I imagine a Marauder fic. So sorry if you followed the other story, but I just didn't want to leave it there, indefinitely. Please send me reviews for this! I started it in my Chinese class, so there's some Chinese in between the paragraphs, I'm going to be careful ;) Hope you like this!**

 **XXXXXXX**

 _ **Pea's POV**_

After bidding my parents goodbye, I ran to Sirius. Even though he was in Gryffindor (reason why my parents despised him, and I looked up to him), and I was most likely going to Slytherin, which I hated having to do, he was the only one who genuinely cared for me. I found him laughing with three other boys, it seemed they were the ones Sirius told me about. James should probably be the bespectacled boy with the wild black hair, Peter the mousy-looking chubby boy, and Remus must be the last one. The scars on his face and neck caught my eye, and I stayed there for a few minutes just staring at them. He felt me looking and looked back at me, and I immediately blushed and turned away, facing my brother. I pulled on his sleeve and Sirius looked at me.

"What is it, Pea?" _He uses my nickname in front of his friends! Cool!_

I blushed harder and whispered,

"For the train ride, can I ride with you? I'm scared of the people Regulus is with…"

Sirius put his hand on my shoulder, under the gaze of the three other boys.

"Cassiopeia you are welcome to our compartment even if you become a Slytherin, now and always. You'll always be welcome to sit with us if you want to, right boys?"

He smiled in the direction of his friends, and they all nodded. Remus also added,

"Sure, Padfoot. Anyone you like, we like."

Sirius's smile grew wider.

"Thanks, Moony. Pea, this is Remus," he nodded to Scar Boy, "this is Peter," he pointed to Mouse Boy, "and this is James," he gestured to Glasses Boy, "Boys, this is Cassiopeia-"

I cut him off, "But don't call me Cassiopeia, call me Pea, please."

They all grinned and nodded. We made our way to the boy's compartment, and I took the seat between the window and Sirius. I leaned on my brother's shoulder and fell asleep.

 **Padfoot's POV**

My sister always falls asleep as soon as she enters a train. I guess it's good for her. Anyways, I had matters to discuss with the boys…

"Boys, do we let Pea on to our secrets? She always keeps secrets. She is _perfect_ at that, and at lying. She looks innocent, but don't let that fool you."

I winked at the boys, and waited for their answer. Moony spoke first.

"I find her really nice, but do we tell her… Everything? I mean, including my… Problem?"

 _Sirius: 1/ Secrets: 0_

James piped up.

"If Padfoot trusts her, I trust her. I vote that we tell her everything."

 _Sirius: 2/ Secrets: 0_

Peter opened his mouth and said,

"I agree with Prongs. If Padfoot says she can be trusted, and that she's good at lying, maybe she'll fool McGonnagall…"

 _Sirius: 3/ Secrets: 0_

Moony gave verdict.

"If you guys think it's okay… I guess I'm okay too."

 _Sirius: 4/ Secrets: 0_

I had bid my time well. Now for the bomb…

"She also is an Animagus."

Their three mouths opened in unison, it was hilarious!

James: WHAT?

Remus: Uh, wait, WHAT?

Peter: AZJOZFJJZZEKF!

I grinned.

"What does she change into?"

Remus always asks the good questions. I shook Pea awake and whispered in her ear,

"Pea, change into your Animagus form. Go on!"

She nodded and closed her eyes. Suddenly she started shrinking and in her place stood a snowy owl.

"Marauders, I proudly present to you Miss Wingy, a snowy owl Animagus. I guess she's officially part of the Marauders now, isn't she?"


	2. Chapter 2: Almost getting Sorted

" _ **Marauders, I proudly present to you Miss Wingy, a snowy owl Animagus. I guess she's officially part of the Marauders now, isn't she?"**_

They all agreed, still dumbfounded after my bomb. I nodded to my sister, wanting her to change back. The owl glared at me, then stared at the pile of clothes surrounding it. I then realized… Pea is a _girl_. We happen to be _boys_. When she morphs back, she'll be _naked_. I looked at the others with murder in my eyes.

"Guys, get out."

James, as thick as he always is, was surprised.

"Why?"

"Pea is a _girl_. She has the right to _privacy_!"

Remus and Peter both had the decency to turn bright red, and Moony even dragged the two boys outside. They could be so thick, sometimes. I then looked at Pea, or Ms. Wingy, and she changed back into herself.

"Your friend James is thick."

I laughed and agreed. She took out her uniform, as did I. While she got dressed, I took something out of my trunks I had been keeping for her since the end of my first year. When she turned around, I held out my first Gryffindor tie.

"Even if you become a Snake, you'll always have some Lion in you, you'll always be my favorite Pea."

 **Pea's POV**

Tears welled up in my eyes. I knew how important this tie was to Sirius, it marked the day he had broken free from our parent's pure-blood Slytherin grasp. Hands shaking, tears rolling down mine and Sirius's faces, I put the tie on and hid it under my collar, so no one would see it, but we'd both know where it was. After that, I jumped into Sirius's arms, sobbing. He caught me in his arms and we stayed like that until someone opened the compartment door, and who came in but Regulus. My other brother. Who hated his older brother's guts as much as Sirius hated Reg's. Sirius clenched his jaw as Reg did the same, and I couldn't help but notice how much they were alike.

"You know, Cassie, you should stay with worthier people next time you ride the train."

I turned all red and next thing I knew, I was yelling my lungs off. This was too much. First our parents made Sirius sound as if he had killed a man, or better, had killed a pure-blood, now Reg copied them. I couldn't stand it anymore.

"WORTHIER PEOPLE? BECAUSE YOU THINK YOU FIT INTO THAT CATEGORY? AS FAR AS I KNOW, IF I WAS TO STAY WITH 'WORTHIER PEOPLE' I WOULD STAY WITH WHO I AM, BECAUSE JAMES, PETER, REMUS AND SIRIUS ARE WORTH TWENTY OF YOU AND ALL YOUR PURE-BLOOD FRIENDS, AND I DON'T CARE ABOUT THEIR LINEAGE! BLOOD DOESN'T MAKE YOU WHO YOU ARE, YOU ACTIONS DO! AS FAR AS I KNOW, THE FEW MINUTES I SPENT WITH REMUS (who walked in, hearing his name, arching an eyebrow, but I didn't notice), WHO IS HALF-BLOOD, MAKES HIM PURER THAN ANY OF US! PETER, WHOSE MOTHER IS MUGGLE, AND PETER DOESN'T KNOW HIS FATHER, MIGHT BE MUGGLE-BORN, IS PURER THAN YOU! I DESPISE YOU, REGULUS, YOU AND ALL OF OUR FAMILY, BESIDES UNCLE ALPHARD AND SIRIUS, I EVEN DESPISE MYSELF FOR BEING PART OF THE BLACK FAMILY!"

I stopped yelling and Reg backed out the door. Remus looked at me and smiled.

"Well, well, Pea, you seem to have a nice pair of lungs!"

We all burst out laughing, and we didn't stop until we got to the Hogwarts platform. Sirius then led me outside up to where a huge, bearded man stood, surrounded by first years.

"Hagrid, this is Cassiopeia, aka Pea. She's my little sister, it's her first year at Hogwarts."

The giant looked at me and smiled. I already loved him!

"Oho, so this is lil' Pea? Yup, Sirius here told me all 'bout yah, from yah birthday to yah favorite color, 1st of June an' burgundy."

I looked at Sirius and he was all red in the face. If looks could kill, Hagrid would be _long_ gone. The game keeper led all the first years to a dock where a ton of long, thin black boats were waiting. I got in the first one, followed by a blond-haired girl, a pink- haired girl ( _I loved her color! Too cool_ ) and a brown-haired girl. I asked them their names and the blond one answered in a dreamy voice:

"Pandora… and you?"

"I'm Cassiopeia, but call me Pea or Cassie, I hate my name!"

The other girl giggled.

"Yeah, I can sort of see why! I'm Alice, by the way. You can call me Al, or Lice, I don't quite care!"

The pink-haired girl was last.

"I'm Nymphadora Tonks. Call me Tonks, you can see why."

We all nodded and I hoped they would all be sorted into Gryffindor with me. We all gasped at the magnificent castle standing before our eyes. I then fully realized it would be my home for the next seven years. That's long! Once we got to the quay, Tonks tripped over Alice's feet, pushed Pandora who made me topple. We all fell into a heap of giggling limbs, and we couldn't get up so Hagrid had to pick us up. We caught up with the other first years just in time to walk into the Great Hall. There, Professor McGonagall called our names, and obviously I was called first, my name starting with the Letter "B".

"Cassiopeia Black!"


	3. Finally Sorted, and in big trouble soon

I awkwardly walked up to the stool, and sat down. I locked eyes with Sirius, and waited as the Hat was placed upon my head by Pr. McGonagall. I waited. And waited. And waited. Thirty minutes easily went by, before the Hat finally spoke.

"This child would dwell in any of the Houses. She is brave, smart, loyal, and resourceful. It is up to her to decide."

My mouth fell open, and I noticed both my brothers gesturing to me. But what made me decide was Alice, Pandora and Tonks all mouthing 'Gryffindor'. So I went with it.

"Gryffindor."

The House I'd chosen erupted into cheers and as soon as McGonagall took the Hat off my scalp, I rushed to Sirius and hugged him tight. I eagerly waited for Pandora to be Sorted, Gryffindor, Alice, Gryffindor, and Tonks, Gryffindor as well. (A/N I know Tonks is Hufflepuff but for the sake of Pea, let's say she's Gryffindor) At the end of the Sorting, Headmaster Dumbledore stood up and said, "I would love to give a nice speech, but by your hungry faces, I can tell you can't wait to eat. So tuck in!"

At our table, even though everyone was cheering, I heard to redhaired twins yell "Hear, hear!". I asked Sirius who they were, and he told me they were Molly Prewett's older brothers, and that Molly happened to be our Prefect. I nodded and started eating.


End file.
